EURASIP Journal on Applied Signal Processing 
Volume 2005 (2005), Issue 19, Pages 3152-3155
doi:10.1155/ASP.2005.3152

EEG-Based Asynchronous BCI Controls Functional Electrical Stimulation in a Tetraplegic Patient

Gert Pfurtscheller,1 Gernot R. Müller-Putz,2 Jörg Pfurtscheller,3 and Rüdiger Rupp4

 1Laboratory of Brain-Computer Interfaces, Institute of Computer Graphics and Vision, and Ludwig Boltzmann-Institute for Medical Informatics and Neuroinformatics, Graz University of Technology, Inffeldgasse 16a, Graz 8010, Austria
2Laboratory of Brain-Computer Interfaces, Institute of Computer Graphics and Vision, Graz University of Technology, Inffeldgasse 16a, Graz 8010, Austria
3Department of Traumatology, Hospital Villach, Nikolaigasse 43, Villach 9400, Austria
4Department II, Orthopedic Hospital of Heidelberg University, Schlierbacher Landstraße 200a, Heidelberg 69118, Germany
Received 29 January 2004

Abstract

The present study reports on the use of an EEG-based asynchronous (uncued, user-driven) brain-computer interface (BCI) for the control of functional electrical stimulation (FES). By the application of FES, noninvasive restoration of hand grasp function in a tetraplegic patient was achieved. The patient was able to induce bursts of beta oscillations by imagination of foot movement. These beta oscillations were recorded in a one EEG-channel configuration, bandpass filtered and squared. When this beta activity exceeded a predefined threshold, a trigger for the FES was generated. Whenever the trigger was detected, a subsequent switching of a grasp sequence composed of 4 phases occurred. The patient was able to grasp a glass with the paralyzed hand completely on his own without additional help or other technical aids.